i am getting a hum through my speakers when i have my xp2016 plugged into the mp2016, when i power down the xp2016 the hum goes away.

also, the external power supply for the units, the one i am using on the mp is about 2 metres from the 230v end to the rj45 end, but the one i am using on the xp is about 300mm from the 230v end to the rj45 end, is is possible to purchase longer power supplies?